Disturbance observer-based control of a dual output LLC converter for solid state lighting applications

Roes, M. G. L.; Duarte, J.L.; Hendrix, M.A.M.

doi:10.1109/ipec.2010.5542073

Cited by 6 publications

(7 citation statements)

References 13 publications

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“…In general, the fundamental harmonic approximation (FHA) model is suitable for analysing the output voltage of the ideal LLC resonant converter that works under light-load conditions [13]- [19]. For the actual LLC converter, the junction capacitor of the secondary-side rectifier diodes and the stray capacitance of the transformer consists of the stray capacitance of the converter [20]- [22]. Meanwhile, the stray capacitance induces an additional extreme point that causes the voltage gain distortion under the light-load condition [17]- [24].…”

Section: Figure 1 Conventional Isolated Llc Resonant Convertermentioning

confidence: 99%

A New LLSC Series Quasi-Resonant Converter With Narrow Switching Frequency Variation

Zhu

Wang

et al. 2020

IEEE Access

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Symbol Quantity Ceq Equivalent capacitance C Basic capacitance ɑ phase shift M Voltage gain fr Resonant frequency fs Switching frequency k Inductance ratio Q Quality factor Lr Resonant inductance Lm Transformer inductance Cr Resonant capacitance Cs Stray capacitance Rac Equivalent AC load ILr Resonant current Ibyp Bypass current Pt Apparent power Kg Magnetic core geometric Kf Waveform factor BAC Window factor ABSTRACT In this paper, the FHA model including the stray capacitance is analysed. The causes of the voltage gain distortion are studied. Limiting the working frequency is an effective method to solve the voltage gain distortion problem. A new type of the LLSC converter is proposed in the paper. It can regulate the voltage at a constant frequency. At the same time, the soft switch can be realized if the parameter design is reasonable. The proposed converter can overcome the voltage gain distortion problem and obtain the high efficiency at the light load condition. Some mathematical analyses are used to prove that the proposed converter can avoid the voltage gain distortion problems. The simulation and experimental results based on a 200W LLSC converter prototype confirm the correctness of the topology.

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Section: Figure 1 Conventional Isolated Llc Resonant Convertermentioning

confidence: 99%

A New LLSC Series Quasi-Resonant Converter With Narrow Switching Frequency Variation

Zhu

Wang

et al. 2020

IEEE Access

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“…In [21], the robust control methods are developed to deal with the uncertainties in the PET model. In [28], LQG control method is applied with an observer to estimate the disturbance due to temperature. However, these work has not addressed two issues in controlling the PET dynamics of LEDs.…”

Section: Introductionmentioning

confidence: 99%

Identification and Robust Control of the Nonlinear Photoelectrothermal Dynamics of LED Systems

Dong

Zhang

2017

IEEE Trans. Ind. Electron.

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In lighting systems consisting light emitting diodes (LEDs), excessive temperature is a main cause of degraded luminous efficacy, which leads to reduced average illuminance and distorted illumination rendering. Modeling the thermal dynamics of LEDs is hence essential in designing thermal dissipators and controllers for maintaining constant illuminance or chromaticity. In the existing literature, both physical modeling and system identification have been proposed, which all find the dependence of the temperature on the input power. When the power fluctuates, e.g. due to dimming control, the thermal dynamics becomes nonlinear. Moreover, when a photoelectrothermal (PET) model is used in control synthesis, the nonlinearity due to the product of the temperature dependent efficacy and the input power must be considered. These nonlinearities are either ignored or linearized in most existing methods. The main contribution of this work is treating the aforementioned nonlinearities in a linear parameter varying (LPV) framework. First, the nonlinear thermal dynamics is identified by LPV system identification techniques. Then, a controller to track reference illuminance is designed by H∞ control techniques to be robust to both the temperature and the disturbance from ambient light. The identification data and the designed controller are collected from and verified on real experimental setup.

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“…This issue relates to the optimal control method such as LQ/LQG control. LQG controller has been applied in various engineering systems such as power converter system [23][24][25], atomic force microscope [26], and wind turbine [27].…”

Section: Introductionmentioning

confidence: 99%

Active Vibration Control of the Flexible Rotor to Pass the First Bending Critical Speed in High Energy Density Magnetically Suspended Motor

Tang

Fang

Zheng

et al. 2015

Journal of Engineering for Gas Turbines and Power

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In order to minimizing the rotor displacement and the amplifier current mainly caused by the unbalance forces when the flexible rotor passes the first bending critical speed, the optimal controller is presented in this paper. The accurate modeling method for the flexible rotor based on the sine sweeping measurements is investigated. The design of the Kalman estimator and the choice of the variance matrix elements have been described. The optimal state feedback regulator with an integral controller has been used for stabilizing the system and the determination of the weight matrices has been investigated in detail. The influences of the specific elements of the weight matrices on the resonance peak of the flexible rotor when passing the first bending critical speed are analyzed. Finally, the running up test of the flexible rotor is implemented and the result shows the effectiveness of linear quadratic Gaussian (LQG) controller minimizing the rotor displacement and the amplifier current nearby the first bending critical speed. Furthermore, the comparison between the proportional-integral-differential (PID) controller with phase lead compensator and the LQG controller verifies the superiority of LQG controller in reducing the amplifier currents.

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Disturbance observer-based control of a dual output LLC converter for solid state lighting applications

Cited by 6 publications

References 13 publications

A New LLSC Series Quasi-Resonant Converter With Narrow Switching Frequency Variation

A New LLSC Series Quasi-Resonant Converter With Narrow Switching Frequency Variation

Identification and Robust Control of the Nonlinear Photoelectrothermal Dynamics of LED Systems

Active Vibration Control of the Flexible Rotor to Pass the First Bending Critical Speed in High Energy Density Magnetically Suspended Motor

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